It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with him) that he said: Sayyiduna Abu Bakr (may Allah be pleased with him) asked the Prophet (peace and blessings of Allah be upon him), "Tell me a supplication that I may say in my prayer." He said: Say, «اللهم إني ظلمت نفسي ظلماً كثيراً، ولا يغفر الذنوب إلا أنت، فاغفر لي من عندك مغفرة، إنك أنت الغفور الرحيم» "I have wronged myself greatly, and none forgives sins except You, so forgive me with a complete forgiveness, for You are the Most Forgiving, Most Merciful."